Regenerative ring impeller pump

ABSTRACT

A regenerative pump for an automotive fuel pump assembly comprises a cover and body that define a chamber and a ring impeller disposed within the chamber. An inlet is formed in the cover, and a discharge port is formed in the body. The body includes a pumping channel adjacent the chamber and having a discharge end section extending from the discharge port. The port diameter is greater than the radial width of the discharge end section. Also, the discharge end section has a depth that progressively increases adjacent the discharge port. The configuration of the discharge port and the channel end section reduces frictional and turbulent losses and thereby improves pumping efficiency.

TECHNICAL FIELD

[0001] This invention relates to a regenerative pump that includes a ring impeller rotatably disposed within a chamber defined by a cover and a body. More particularly, this invention relates to such regenerative pump that includes a pumping channel discharge port that are cooperatively configured to improve pumping efficiency.

BACKGROUND OF THE INVENTION

[0002] An automotive vehicle comprises a fuel pump assembly for pumping fuel from a fuel tank to an internal combustion engine. The fuel pump assembly is typically located within the fuel tank and includes a shell that defines a compartment and an electric motor disposed within the compartment. The pump elements include a cover and a body that define a chamber. An impeller is disposed within the chamber and driven by the electric motor. An inlet is formed in the cover for drawing fuel from the tank into the pump. The pump includes a discharge port that discharges fuel into the compartment. An outlet from the compartment is connected to a fuel line that leads to the engine.

[0003] Regenerative pumps are known that include a ring impeller. The ring impeller features a continuous circumference and vanes inboard from the circumference. Pumping channels formed in the cover and the body communicate with the inlet and the discharge port, respectively, and cooperate with the vanes of the impeller to provide regenerative fluid flow through the chamber.

[0004] The efficiency of the pump is reduced by turbulence in fluid flowing through the discharge port. To reduce turbulence, it is conventional practice to enlarge the discharge port and to progressively widen the channel adjacent the discharge port. However, fluid pressure within the wider channel applies an axial destabilizing force to the solid regions of the ring impeller about the vanes and increases frictional losses within the pump, thereby also reducing pump efficiency.

[0005] Therefore, a need exists for a regenerative ring impeller pump that includes a pumping channel and a discharge port formed in a body and reduces turbulence in fluid flow from the channel into the discharge port, without widening the channel adjacent the discharge port and without applying destabilizing pressure on the ring impeller.

BRIEF SUMMARY OF THE INVENTION

[0006] This invention provides a regenerative fuel pump having an improved discharge port configuration, and an automotive fuel pump assembly comprising the regenerative pump. The pump comprises a housing that includes a body and a cover that define a chamber. A ring impeller is received in the chamber and is rotatable about an axis. A pump inlet is formed in the cover for supplying fluid to the chamber. A discharge port is formed in the body for discharging fluid from the chamber. A pumping channel is formed in the body adjacent the chamber and includes a discharge section extending from the discharge port. In accordance with this invention, the discharge section features a substantially constant radial width, and the port radial dimension is greater than the width of the discharge section. Furthermore, the discharge section has an axial depth that progressively increases adjacent the discharge port. By providing a constant width in the channel end section, the regenerative pump avoids applying forces about the vanes of the impeller that would tend to destabilize the impeller, and thus minimizes frictional losses associated with impeller rotation. In addition, the enlarged discharge port radial dimension and progressively deeper end section reduces fluid flow velocity through the discharge port that would otherwise produce turbulence. As a result, the fuel pump having a discharge configuration in accordance with this invention improves pumping efficiency by between about 5 and 10 percent compared to pumps having progressively wider channel sections.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] This invention will be further described with reference to the accompanying drawings wherein:

[0008]FIG. 1 is a cross-sectional view of an automotive fuel pump assembly having a regenerative ring impeller pump in accordance with this invention;

[0009]FIG. 2 is an exploded perspective view showing the elements of the pump in FIG. 1;

[0010]FIG. 3 is a cross-sectional view of the pump, taken along lines 3-3 in FIG. 1 in the direction of the arrows; and

[0011]FIG. 4 is a cross-sectional view of a portion of the pump in FIG. 1, taken along lines 4-4 in FIG. 3 and in the direction of the arrows.

DETAILED DESCRIPTION OF THE INVENTION

[0012] In accordance with the preferred embodiment of this invention, an automotive fuel pump assembly 10 in FIG. 1 comprises a regenerative fuel pump 12, further depicted in FIGS. 2-4. Fuel pump assembly 10 is adapted to be installed in a fuel tank of an automotive vehicle for pumping fuel to an internal combustion engine. Fuel pump assembly 10 comprises a shell 14 that encloses a compartment 16. An electric motor 18 is located within compartment 16 and includes a shaft 20 that rotates about rotational axis 21 to drive the pump. During operation, fuel is pumped by pump 12 into compartment 16 and flows from compartment 16 through outlet 22, which outlet is connected to a fuel line that leads to the engine.

[0013] Regenerative fuel pump 12 comprises a cover 24 and a body 26 that define a pumping chamber 28. A ring impeller 30 is rotatably disposed within pumping chamber 28 and is mounted onto shaft 20 to be rotated by motor 18 about axis 21 in direction 23. Cover 24 is disposed in an end of shell 14 and includes an inlet 32 for drawing fuel from the fuel tank into pumping chamber 28. Body 26 divides pumping chamber 28 from compartment 16 and includes a discharge port 40 for discharging fuel from chamber 28 into compartment 26.

[0014] Ring impeller 30 comprises a continuous circular circumference 34 and a plurality of generally radial vanes 36 spaced inboard from circumference 34. Cover 24 comprises a pumping channel 38 that extends from inlet 32 circularly about the axis to a point near, but spaced apart from the inlet and registers with vanes 36. Also, body 26 includes a pumping channel 42 that circularly extends about the axis from the discharge port 40 to a location near, but spaced apart form the discharge port and registers with vanes 36. The radial width and axial depth are designed of channels 38 and 42 to optimize regenerative fluid flow through the channels. During operation, vanes 36 cause fluid to flow through channels 38 and 42 from inlet 32 in route to discharge port 40.

[0015] In accordance with this invention, discharge port 40 and channel 42 are sized and shaped to enhance pumping efficiency. Referring particularly to FIG. 4, discharge port 40 is cylindrical about an axis 44 parallel to axis 21 and extends between an opening 46 adjacent the pumping chamber 28 and an opening 48 adjacent compartment 16. Channel 42 includes a discharge end section 50 that extends from opening 46. It is a feature of this invention that channel 42 including end section 50, has a substantially constant radial width that corresponds to the radial length of vanes 36 to optimize regenerative fluid flow through the channel. Discharge port 40 comprises an enlarged radial dimension greater than the channel radial width. Although a discharge port is shown in the Figures to have a circular cross section, the cross section may suitably be oval, elliptical or other noncircular shape. Preferably, the port radial dimension is between about 1.2 and 1.5 times the channel width. End section 50 extends over an angle a in an arc about axis 21. In general, it is desired to minimize the length of end section 50 to maximize the extent of the channel having the optimum design for regenerative fluid flow with the impeller, while providing sufficient length to reduce fluid velocity into the discharge port and thereby minimize turbulence. An angle a of at least 20° is believed to be effective to minimize turbulence into the discharge port. An angle a greater than about 40° is believed to reduce the efficiency of the pump by diminishing the optimum channel design without further advantage relative to discharge port flow. By way of preferred example, it is believed that an angle a of 30° provides optimum regenerative fluid flow through the channel and reduced turbulent flow through the discharge port.

[0016] End section 50 features an axial depth measured from face 52 that progressively increases in proximity to discharge port 40. In general, it is desired to increase the cross section into which the fluid is pumped and thereby reduce the fluid velocity, and to direct fluid at a shallow angle into the discharge port, to minimize turbulence. Preferably, end section 50 has a straight centerline 54 that intersects axis 44 at an angle b between 50° and 70°. By way of a particular example, an angle b of 60° is believed to be optimal. Also, preferably, the area of the cross section of port 40 is between about 2 and 5 times the cross-sectional area of channel 42 outside end section 50.

[0017] Body 26 includes a face 56 adjacent compartment 16. In a preferred embodiment, discharge port 40 includes a groove 58 that extends from opening 48 in a direction opposite end section 50. Groove 58 features a sloped surface that progressively increases adjacent the discharge port. In a preferred embodiment, sloped surface 58 extends along the line 60 that intersects axis 44 at an angle of between about 50° and 70°, optimally 60°.

[0018] During operation, electrical power is supplied to motor 18 to rotate shaft 20 and thereby drive ring impeller 30 about axis 21 in direction 23. Fuel is drawn from the fuel tank through inlet 32 and is pumped by vanes 36 through channels 38 and 42. Fluid flows through end section 50 into discharge port 40, and is discharged from port 40 through opening 48 into groove 58 and compartment 16 and eventually through outlet 22 to the engine. It is an advantage of the discharge port configuration of this invention, that end section 50 features a substantially constant width consistent with the upstream section of channel 42. Thus, end section 50 does not extend over the solid regions of ring impeller 30 inboard and outboard from vanes 36 and thus does not apply a destabilizing axial force to these regions that would otherwise interfere with smooth rotation of ring impeller 30 and create frictional losses that would reduce pump efficiency. It is still a further advantage of this invention that discharge port 40 has a radial dimension greater than the width of end section 50. The enlarged dimension reduces fluid velocity through the discharge port while maintaining fluid pressure, thereby preventing flow losses through the discharge port. Still further, in the preferred embodiment, discharge port features a groove 58 to reduce turbulent losses of fuel entering compartment 16. By reducing friction and turbulent losses through the discharge port, this invention improves pumping efficiency between about 5 and 10 percent.

[0019] While this invention has been described in terms of certain embodiments thereof, it is not intended to be so limited, but rather only to the extent set forth in the claims that follow. 

1. A regenerative pump comprising: a pump housing comprising a body and a cover defining a chamber; a ring impeller received in said chamber and rotatable about an axis; a pump inlet in said cover for supplying fluid to said chamber; a discharge port in said body for discharging fluid from said chamber and having a port radial dimension; a pumping channel formed in said body adjacent said chamber and comprising a discharge end section extending from said discharge port, said discharge end section having a substantially constant radial width, said port diameter and said radial width being sized such that said port radial dimension is greater than said radial width, said end section further comprising an axial depth that progressively increases adjacent said discharge port.
 2. A pump in accordance with claim 1 wherein said discharge end section in an arc that extends over an angle between about 20° and 40° relative to the axis.
 3. A pump in accordance with claim 1 wherein the depth of the discharge end section includes a centerline increases at an angle between about 50° and 70° relative to the axis.
 4. A pump in accordance with claim 1 wherein said discharge port comprises a coaxial circular passage.
 5. A pump in accordance with claim 1 wherein said body includes an outer face opposite said chamber, and wherein said discharge port includes an outer opening at said outer face, and further wherein said outer face defines an outer channel extending from said outer opening.
 6. A pump in accordance with claim 5 wherein the outer channel extends from said outer opening at an angle between about 20° to 40° relative to the axis.
 7. A pump in accordance with claim 1 wherein the ring impeller has a continuous circumference and vanes spaced inwardly from said circumference.
 8. A pump in accordance with claim 1 wherein the discharge port has a radial dimension between 1.2 and 1.5 times the radial width of the discharge end section.
 9. An automotive fuel pump assembly comprising: a shell defining a compartment and having a shell end; an electric motor disposed within the compartment and having a shaft rotatable about an axis; a pump housing comprising a cover disposed in said shell end and a body inboard the cover, said cover and body defining a chamber; a ring impeller rotatably received in said chamber and mounted on the shaft; a pump inlet in said cover for supplying fluid to said chamber; a discharge port in said body for discharging fluid from said chamber to said compartment and having a radial dimension diameter; a pumping channel formed in said body adjacent said chamber and comprising a discharge end section extending from said discharge port, said discharge end section having a substantially constant radial width, said port diameter and said radial width being sized such that said port radial dimension is greater than said radial width, said end section further comprising an axial depth that progressively increases adjacent said discharge port, whereby the port diameter is greater than the radial width of the pumping channel.
 10. An automotive fuel pump assembly in accordance with claim 9 wherein said discharge end section extends over an angle between about 20° and 40° relative to axis.
 11. An automotive fuel pump assembly in accordance with claim 9 wherein the depth of the discharge end section increases at an angle between about 20° and 40° relative to the axis.
 12. An automotive fuel pump assembly in accordance with claim 9 wherein said discharge port comprises a coaxial circular passage.
 13. An automotive fuel pump assembly in accordance with claim 9 wherein said body includes an outer face adjacent the compartment, and wherein said discharge port includes an outer opening at said outer face, and further wherein said outer face defines an outer channel extending from said outer opening.
 14. An automotive fuel pump assembly in accordance with claim 13 wherein the outer channel extends from said outer opening at an angle between about 20° and 40° relative to the axis.
 15. An automotive fuel pump assembly in accordance with claim 9 wherein the ring impeller has a continuous circumference and vanes spaced inwardly from said circumference.
 16. An automotive fuel pump assembly in accordance with claim 9 wherein the discharge port has a diameter between 1.2 and 1.5 times the radial width of the discharge section.
 17. An automotive fuel pump assembly in accordance with claim 9 wherein the discharge port has a cross-sectional area and wherein the pumping channel has a cross-sectional area outside the end section, and wherein the cross-sectional area of the discharge port is between 3 and 5 times the cross-sectional area of the pumping channel. 